


Unseen Enemy

by Justdumbfics



Series: (Unseen) Practical Problems in the Stone World [2]
Category: Dr. STONE (Anime), Dr. STONE (Manga)
Genre: Gen, I'll update tags as I go I guess?, Oh wait, also legit like illness in the stone world would be p bad and is an interesting thing to explore imo, im british and bitter, lets imagine a world where we actually handle pandemics with science and good leadership lmao, pandemic with a happy ending, thats just new zealand!
Language: English
Status: Completed
Published: 2020-11-19
Updated: 2020-12-14
Packaged: 2021-03-09 23:35:48
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 4
Words: 12,124
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27624158
Author URL: https://archiveofourown.org/users/Justdumbfics/pseuds/Justdumbfics
Summary: ** This is a happy story - if you want to read something about some dumbasses overcoming a pandemic (or need to read something like that), you're in the right place! There will be some struggling but ultimately everything ends well i promise haha but also if you're finding pandemic related things kind of triggering right now then maybe avoid this one!Being 3700 years old means only being resistant to diseases that have, unfortunately, had 3700 years to mutate.Part 2 (both parts can 100% be read as standalone works) of my practical problems of the stone world series! Viruses mutate!!! The old humans would have seriously bad immunity!!!Spoilers up to completion of Perseus i guess?
Relationships: Asagiri Gen & Ishigami Senkuu, Chrome & Ishigami Senkuu
Series: (Unseen) Practical Problems in the Stone World [2]
Series URL: https://archiveofourown.org/series/2019683
Comments: 25
Kudos: 80





	1. Stage 1: Isolation & Preparation

**Author's Note:**

> Hello! As a bit of a disclaimer, my field of research is actually astrophysics, not anything related to biology, so I'm the wrong kind of scientist for this? I think I have a good enough understanding for this fic and have also done some research, but honestly trying to predict how the world would develop in 3700 years if humanity (save 4 people) just stopped is such a dodgy business lmao I love these kinds of discussions though so feel free to message if you have any ideas/questions/suggestions about the science!

This was a stone world.

The first scientific thing Senku had made upon awakening was soap. This was not because he happened to have the materials, or because it was easy, no - it was because, as he had said, illness was the absolute worst thing that could happen to them. With ten million percent certainty, they could not cope with mass disease in a world with no medicine. Senku could make antibiotics, given time and a metric shittonne of materials, sure, but they'd been lucky that it had worked for Ruri. It was a measured risk, since the sulfa drugs work for so many illnesses, but a risk nonetheless.

For something like, say, an outbreak of some new viral infection? There wasn't shit they could do. 

But, of course, being people raised with immunity to the infections of a world 3700 years old, they had practically no resistance to the horde of new diseases all around them.

An outbreak was completely expected, unless they were very good at keeping clean. Unfortunately, Senku realised belatedly, he had been too busy with other projects to really hammer that point home.

Ryuusui was down. His lungs were shot. It sounded similar to pneumonia, with fever and other nasty symptoms along with it. If Senku had to guess, he'd say it was a flu - but a kind which was used to feeding off the gorilla-humans of this age rather than their weak 3700 year old asses. This was absolutely, ten million percent, _not_ what they needed. 

"Alright, everyone needs to self-isolate!" Senku announced, facing the crowd of villagers. They had all gathered when it became clear that something was wrong. They looked to their leader now, eyes wide with concern. 

It was the night before the Perseus up-scale was due to begin. What a downer, Ryuusui's model was looking absolutely exhilarating. It would be a time sink, too. Winter wasn't far off, though, and losing manpower to a shitty flu season would not be acceptable. 

"Self-what now?" Ginro whined.

"Self isolate…" Gen repeated quietly, from his position just behind Senku. "But Senku-chan, surely if this is infectious, we would've all caught it from Ryuusui-chan already?"

Senku shook his head, speaking over his shoulder to Gen, "Ryuusui has been cooped up making his model, remember? I estimate only a handful of us have been in contact with him." Senku paused, turning slowly toward the crowd again, a look of horror on his face. 

"A handful of people… who are now spreading the disease in this crowd." Gen concluded.

"I'LL EXPLAIN LATER!" Senku barked to the people of the Kingdom, "EVERYONE, GET TO YOUR HOMES, NOW!"

Senku putting on his Serious Voice was clearly enough to convince the Kingdom of Science that the situation was urgent. They all rushed back to their homes, clamouring inside. 

Senku sighed.

Gen cleared his throat quietly from behind him. "Have _you_ seen Ryuusui recently…?" Senku could hear the carefully crafted calm in Gen's tone; even a mentalist could be read if you spent enough time together. Gen was scared. 

Senku shook his head, "Not really, but we have no idea what the incubation period for this thing is. Or how it's spread. Is it airborne? I bet Ryuusui came out to look at the ship a few times, or went to the restaurant. Could it have hung around? We don't know."

He turned around to face Gen properly, taking a step back and covering his mouth and nose with his hand. 

"Until I can figure out more, we're gonna have to be seriously fucking careful."

Gen nodded, covering his face with the sleeve of his haori. "If either of us have caught it though, Senku-chan…"

Senku grimaced behind his hand. "Yeah… then we both have it. And so do the rest of the generals, probably." 

"What's our game plan?"

Senku ran his free hand through his hair, "We isolate until Ryuusui's recovered. By that time, either someone else should have developed symptoms, or we're all safe and it wasn't infectious after all. Unless it has a seriously fucking long incubation… if that's the case though, we'd have all caught it off Ryuusui and Francois anyway, so we'd be best off putting all our hands to work on making painkillers, or something. Prevention would be off the cards. We need to try and pinpoint how he got the damn thing in the first place, too."

"And you intend to do these things simultaneously, how…?" 

Senku's mouth slid up into a smirk, "Like you don't know the answer to that. _Science_ , Asagiri Gen."

Gen couldn't contain his chuckle, shaking his head. "You're insane."

"We're going to get through this." 

Gen’s smile was sharp, the fear in his voice replaced with steadfast determination, "I know."

\--- * --- * ---

After giving Gen a more detailed explanation of his plans ("You can't just say _science_ senku what does that even _mean_?"), Senku drew up the blueprints for a face mask, sliding it under Yuzuriha's door. 

"I need you to make these, but without touching the blueprints I just gave you."

"Pattern." Yuzuriha corrected, sounding amused. "Blueprints for sewing are called _patterns_."

"Yeah, okay, pattern!" Senku conceded, "Listen, don’t touch it. We need to minimise physical contact between people. Make your own mask first and wear it while you work. And wash your hands! With soap! Before you start, whenever you touch anything. Got it?"

"Got it!" Yuzuriha called through the door, "One per villager?"

"How much linen do we have?" 

"Enough for more than that. I haven't started on next season's clothing line yet. Maybe three per person, at least?" 

“Alright, great, because I also need you to make these." 

He slipped another blueprint under the door.

"One set for every young adult member of Ishigami village, two sets if possible. That's about 80 sets. If that means people only get one mask each, then so be it. I’m leaving wire out here for you, wash it before you use it in the masks."

“Alright, leave it to me!” 

\--- * --- * ---

Senku’s next stop was the restaurant. Francois was almost definitely infected, and seemed to have realised that fact. 

“I am isolating with Ryuusui-sama.” They said, through the door to the restaurant, “Anything he has caught, I have also most likely caught. I will therefore continue to serve him, as there is no further risk to the two of us." 

Senku nodded, "Yeah… and if you've caught it, most the food supply in there will have it too. Can you-"

"Sterilise the food, of course. Leave the matter to me. I will ensure everyone has the provisions they require, as well as the knowledge to prepare their food safely."

"No,” Senku sighed, “You can't be the one distributing the food if you've almost definitely caught the damn thing."

"What alternative do you suggest?"

"This is what I need you to do, listen up…" 

\--- * --- * ---

Senku was an incredible scientist, but managing a potential pandemic was as much about managing _people_ as it was about science. Although his services had not been expressly requested, Gen knew when he was needed. 

“Kingdom of Science!” He called from a makeshift stand, megaphone in hand. It had been child's play to make after they completed the cell phone, and they figured it would prove very useful when they were working on something as big as the Perseus.

People began peeping out from their doorways, clearly listening. 

“Please refrain from leaving your homes, but listen to me closely!” Gen began, pleased when he saw people hesitantly shuffle further back inside. “What we face today is an enemy even deadlier than Hyouga, or the sulphur gas. Unlike Hyouga, this enemy is invisible. Unlike the gas, it is one even those of us from modern times have never seen before.” 

The air was completely still, the atmosphere almost stifling. They all knew first-hand how dangerous Hyouga was. On top of that, everyone had heard about Ishigami village’s exploits, so they knew how risky the gas situation had been too. They were hanging on his every word. Perfect. Gen searched for Magma amongst the faces; he was a good gauge of how the more... brute-force-inclined of the group were reacting. 

“Ryuusui is very ill. Many of you may remember our success when helping Ruri. This is very different. Ruri’s illness was one we had seen before, and therefore one for which the modern world had discovered medicines. Genius though he is, Senku’s ability to replicate that medicine was contingent on the fact he had that prior knowledge. I have no doubt that, given the time, Senku would be able to find a cure for this, too. Unfortunately, time is one thing we absolutely do not have.”

Finding his target, he caught Magma’s eyes before he spoke again, “Ryuusui is currently struggling to breathe, and is bed-bound.” Magma’s throat bobbed as he swallowed, his eyes wide. Success. “We are caring for him as best we can. The absolute worst-case scenario right now, is the possibility that whatever he has is _infectious._ ” 

The group seemed to collectively hold its breath, eyes wide and mouths just slightly agape. Gen felt a small swell of pride in his chest at how _good_ he was at this. 

“Senku, being the brilliant man he is, realised this instantly. He realised what type of disease this probably was, what the worst-case was, and so ordered you all to return home immediately. The only way to stop us catching the disease from each other, after all, is to limit social contact.” Gen explained. That seemed to elicit a reaction of some relief from the group. Really, the faith these people had in Senku was such a life-saver (quite literally, right now). He’d almost go as far as to say it made his own job _easy_. Almost.

“Thankfully, Ryuusui has been largely alone recently, due to his work on the model. It is still possible, however,” Gen paused, looking around the Kingdom, making eye contact with as many people as possible, “that a handful of us have already caught the disease.” 

People began glancing back and forth, catching each other's eyes. They were nervous. Time to wrap things up.

"This type of disease can sometimes live inside you for a week or two before you feel it. That means you can give it to your friends _before you even know you have it_ !” Gen threw his arms out for emphasis, then. The sudden movement had the desired effect, with half his audience flinching and looking mildly horrified. “It is therefore absolutely _imperative,_ " Gen continued, "We _all_ keep _away_ from each other! This kind of thing can be caught even just by breathing the same air!"

"But what about the boat?!" One of the modern men called. The rest of the people seemed to jump at the sound of another voice, looking for the source with mild irritation written over their facial expressions and body language. 

"The boat can wait, idiot!" Magma snapped. "There won't be anyone around to ride the damn thing if we all get sick!"

Gen blinked. Perhaps he'd sold Magma short in his fast judgement. In fact… glancing around the crowd, the people of Ishigami village seemed to be wearing the hardest expressions. Ah, of course they were. They’d lived through bad winters, even nearly lost their Priestess to pneumonia. The modern people were the ones who weren’t going to understand, with their airy indignance and complete lack of understanding as to the danger of disease. Their privileged pasts would be the death of them.

Gen looked to the man who’d spoken. “Sir, we would all love to get the boat finished. It is as Magma says, though. The health of this nation has become our number one priority.”

The guy looked like he was about to speak, so Gen spoke up first. 

“Your body has been in stone for 3700 years.” He said sharply, making eye contact. “Every disease we were vaccinated against, every disease our bodies have ever seen, has _evolved_ . We have _not_. We could be looking at the smallpox of this age. Do you understand? Think _cancer_ if it was _infectious_.” Gen wished he knew more about the history of medicine, but honestly that was the best he could come up with right now to try and illustrate the reality of their situation. 

The guy, thankfully, shut his mouth. He nodded in what seemed to be reluctant agreement. 

“Good. Senku is working on some disease prevention initiatives. Until he’s done, or we have more news, please stay in your homes. Food and provisions will be distributed in the safest manner possible.” Gen paused before speaking his next words, putting on a smile as sincere as he could manage when in such a full-blown mentalist mindset. “As doom-and-gloom as all of this might sound, try to be hopeful. We beat Hyouga. We beat the gas. We’ll beat this too.” 

\--- * --- * ---

Leaving Francois to their task, Senku’s next stop was Kohaku’s place. Upon returning to the living area of the Kingdom, he was pleasantly surprised to find it entirely empty and silent. He thought for sure some curious idiot would’ve gotten bored and snuck out by now… he really should make some kind of announcement soon to explain what was going on… 

With these thoughts floating around his head, Senku completely forgot to knock when reaching Kohaku’s home. He slipped in, mask in place over his face (Yuzuriha worked _fast_ ), only to be met with a spear at his throat.

“Senku!” Kohaku roared, “What are you _doing_ you can’t be mixing with people!” 

Senku blinked at her, entirely unphased. He picked at his ear with his pinky finger. “Yo, Gorilla. I know that, duh. You’re safe though.” 

“I’m… safe?”

“Yeah.” Senku glanced at his pinky, blew on it briefly, then looked at Kohaku again. “Put this thing down, would you?”

Kohaku moved the spear, looking very confused. “But Gen said…”

Senku’s mouth stretched into a broad grin, so wide that Kohaku could probably see it in his eyes. “Oh, the mentalist already did his job? How efficient. What did he say?”

Kohaku summarised Gen’s words, ending on a question. “So how do you know I’m safe? I could have it!”

Senku nodded, “Yeah, you could. But you’re a gorilla. You and all the other young people from the village? You’re going to be fine. It’s like Gen said, it’s us old-worlders that are in real trouble, since our bodies haven’t changed for 3700 years. You’ve probably developed the immunity you need for whatever this is.” 

“You’re sure?” Kohaku’s shoulders fell slightly, relief painted across her face.

“No.” Senku’s voice was flat. The way Kohaku’s face dropped was seriously _hilarious_ . She then looked like she was going to start a fight though, so Senku thought it best to elaborate. “Look, it _is_ possible that this is a virus or something which you haven’t seen before either. Viruses can randomly mutate, and become something which can replicate inside the human body. That’s seriously fuckin’ rare though. It’s way more likely that this is something your lot have had before, since those are the diseases that are already hanging around in this stone world. There’s got to be ten billion viruses that made that random mutation while we were asleep, infected humans, and carried on replicating. If that’s the type of disease we're dealing with, then even if you catch it, you’ll hardly feel it. You'll have _some_ immunity.” 

Kohaku nodded slowly. “Right… I’m not sure I really understand all of that, but the people who were in stone are probably most at risk?”

“Yes.”

“So people like _you_?”

“Yes…?” 

“So even if I am safe, if I have it and give it to you, that’s still bad?” 

Senku grinned, “Yes. But since I was the first on scene to examine Ryuusui, if it _is_ infectious, I probably already have it anyway.” 

Kohaku gasped, covering her mouth. “Senku, that’s--” 

“Don’t worry.” He said sharply, “We’re going to beat this, like we’ve beaten everything else. I’m playing with measured risks now though. I’m estimating it’s unlikely to be seriously threatening to you and the other young villagers, so I need you to co-ordinate a team to supply provisions to the rest of us while we all stay indoors.” 

“Of course!” Kohaku said earnestly. The concern was still shining in her eyes, but Kohaku was very good at prioritising. She made excellent judgements, and she made them very quickly. 

“I’ll say it again - this is just a measured risk. It’s entirely possible that this is actually the other scenario I mentioned, and you lot can catch it just as badly as us. If that happens, being responsible for delivery of provisions, you’d have the greatest exposure to the disease and so the greatest risk.”

“You’ve already decided I’m doing this though, haven’t you? You wouldn’t have risked coming in here if you hadn’t.” She raised an eyebrow at him. 

Senku smirked, “I knew you wouldn’t say no. Balancing probabilities, this is the Kingdom's best shot at getting through this.”

“I know. I know you wouldn’t ask us to do something dangerous unless it was necessary.” 

Senku nodded slightly. 

“Yuzuriha has made two sets of protective clothing for all of you. Organise it so only about ten of you work at a time. Any more than that and you'll be bumping into each other too often. We're minimising social contact. You wear one set of the clothing when you’re on shift, you take it off and wash it, then wear the other set for your next shift. Repeat. Don’t touch anything you don’t have to touch. Change into something clean as soon as you can after your shift. Wash your hands all the fucking time. Using soap. Got it?” 

“Got it.” 

“Priorities are delivery of food and water, and delivery of the face masks” Senku gestured to the one he was currently wearing, “that Yuzuriha has made. You don’t give anyone their food unless they’re wearing their mask. You don’t speak to anyone unless they’re wearing their mask.”

Kohaku nodded. 

“Alright. Pass that on to the other young, adult villagers. I’m leaving you in charge.” 

“I’ll set out now!” Kohaku said, moving towards the door. 

“One more thing.” Senku said quietly, just as she was about to go. She looked at him, waiting. “Don’t tell anyone I have it. I haven’t even told Gen. Hope is important, to keep people listening to us and following instructions.”

Kohaku sighed quietly, “Yeah… yeah, understood.” 

Senku nodded his head to her, before slipping out and away from the small home. 

Okay. Now, for the science work. 


	2. Stage 2: Organisation & Mobilisation

**Notes for the Chapter:**

> Hello! Thank you for your kind comments on the first chapter & for the kudos! :D Hope you enjoy part 2! &as always, kudos and comments are very much appreciated ^^

Senku’s plan was working like a dream. 

The young adults of Ishigami village had been dubbed the Provisions Team. They received food provisions and instructions from Francois, who had sterilised the kitchen as best they could before retreating into isolation with Ryuusui. Instructions on how to sterilise the food and keep the kitchen area clean were translated to comic form by their resident manga artist, since none of the Provisions Team could read, and displayed around the area. The food was distributed once every day. 

The entire Kingdom had also been provided with facemasks, which they were to wear whenever they had to leave their homes for any reason at all. Common reasons were bathing and the bathroom, though Kohaku had also managed to convince Senku that exercise should count ("Ha! Good luck getting any labour out of them when this is all over!"). 

Only a handful of people were allowed out of their tents at any given time, with members of the Provisions Team keeping an eye on the numbers. 

Honestly, the whole operation was so much smoother than Senku expected it to be. It made him incredibly suspicious as to how Gen had been spending his time. Chances were, they all had him to thank for keeping it on track. 

Gen. 

Senku sighed for the umpteenth time that day. He hated lying. He hated it even more when it put his friends at risk. Maybe if Gen knew he probably had it, since Senku probably had it, he’d be more careful... but, really, he should be careful anyway, right? 

He sighed again. 

It felt wrong. 

But if he told the mentalist the truth, it would only worry him. They knew nothing about this damn thing anyway - there was a non-zero probability he’d be totally fine even if he did catch it! Although, knowing his luck… 

Senku shook his head in an attempt to clear it. He was getting off-track. Taking a deep breath, he forced his mind to return to the task at hand.

He was currently standing in the lab, samples spread out before him. He knew four things for certain: 

  1. Ryuusui was the only person in the Kingdom showing symptoms 
  2. Those symptoms included some kind of damage to the lungs, fever, and a cough.
  3. If it was infectious, Francois should have caught it. 
  4. Ryuusui had to have picked it up from somewhere. 



Facts 1 and 3 combined meant it was possible to discover whether or not the disease was infectious, by comparing samples of Ryuusui and Francois’ saliva. If he found the antigen in both samples, they were in trouble. They had long since completed the equipment he’d need for this level of lab work, so thankfully he could get started on it straight away. After he’d done this, he’d be able to start work on a roadmap - right now, the simple truth was that he did not know what needed to be done. 

And, if he could figure out whether or not people had contracted the disease, he'd be able to test himself. If that came up positive, then, yes, he'd bite the bullet. He'd tell Gen. 

He’d never been so grateful for the research he did on ebola in Africa; it was the perfect training camp for this. 

Senku rolled up his sleeves, and got to work.

* * *

Kohaku was very, very tired. 

It was the kind of bone-deep exhaustion she’d only really gotten when she was a child; the first few times she carried water from the hot springs for Ruri, she’d been completely spent. Actually, she might wager her current state was worse than even that.

It was to be expected, though. She was practically running the Kingdom, and working on empty. She hadn't had a good night's sleep since this whole thing started. The food supplies were good, since they’d started stockpiling for the voyage, but there was no way they could keep up the agriculture work if that stockpile ran out. Hunting for over 100 people would also be a serious challenge. 

She felt a chill go down her spine as she remembered the famine Ishigami village had lived through. 

The science team needed to make serious progress on a cure before it came to that...

She felt a hand on her shoulder, and she quickly looked to its source.

“You okay?” It was Chrome, his brows furrowed in concern.

“Yeah, totally.” Kohaku lied. 

“You don’t look it.” He scrunched up his nose, disapproving. “Take a break.” 

“I’m  _ fine _ . Shouldn’t you be with Senku doing science?” 

Chrome shook his head, glancing over towards the lab. His concern gave way to frustration as he huffed, “Senku wants to use my explorer skills instead. He sent me out to look for anything that could’ve been the source of the disease.” 

“That sounds like a good idea…?” Kohaku ventured, confused by Chrome's clear dissatisfaction. 

“I’d rather be doing something…. I don’t know, useful? It feels like being sent on a wild goose chase while he does the  _ real _ work.”

Kohaku rolled her eyes, “You know he trusts you more than that. He’s obviously putting you to work in the most useful place." The crease between Chrome's eyebrows eased, just slightly. "Now go do your job and let me do mine.” Kohaku finished. 

Chrome sighed. “Fine.” He mumbled. He waved over his shoulder, heading back out on his chores. As he left, Kohaku saw him cough into his hand quietly, despite the mask over his mouth. 

When did he develop that cough? It was nearly winter... it was probably just a cold. 

Yeah. Probably a cold, that’s all.

She walked briskly to her next stop - Taiju’s place. He was one of the few given frequent permission to leave his home; Senku had said anyone involved in the linen making process was to continue their work, but in staggered shifts so only a few of them were working at a time. Apparently, these cover-alls the Provisions Team had been given were quite important, as were the masks. They needed enough linen to replace them if needed. They also needed people making the strange fluffy things which they'd been distributing recently. Senku said he needed everyone to stick one of those in the back of their throat and in their noses, for some science thing. A sample? Kohaku didn't really get it, but it was absolutely crucial, according to the sciencers.

She stopped before her destination. “Taiju?” Kohaku called quietly. “You’re up, if you want to take your shift.” 

“Y-yeah!” Taiju boomed, but his voice seemed off. Unclear. 

He emerged in the doorway, and Kohaku felt her heart drop. 

He was sweating, sniffling, and barely standing up. 

“Get back inside.” Kohaku ordered. “You’re sick.” 

“S’okay,” Taiju said, “Just a fever! I can b-breathe, and stuff, so it’s… it’s not like Ryuusui.” He said with far more confidence than he had any right to have. 

“Senku said  _ any _ of Ryuusui’s symptoms, and you stay in your house.” Kohaku insisted. 

“What…?” Taiju asked, “He did?” 

Man, this guy was  _ out of it.  _

Kohaku took a deep breath, before speaking in the calmest tone she could manage. “Yeah, Taiju, he did. Just, go back inside. I’ll come get you when you’re allowed out, okay? Senku’s orders.”

Taiju nodded. “Senku’s orders… okay…” He turned back around, and barely a moment later Kohaku was sure she heard him collapse back into bed. 

Man. This was not good. 

She stifled a cough of her own, before heading straight towards the lab to inform Senku. 

* * *

Gen scrunched up his nose as he stared at the food he’d been given. 

Boar. 

Recently, the Kingdom had refrained from hunting. With their agricultural work providing a lot of food, Senku had decided it was illogical to waste time and manpower on hunting out in the mountains. When they did hunt, it was the closer herds of goats or they went fishing. 

So where had this boar come from? 

He pushed the tray away, quietly apprehensive. 

When Ruri had delivered it, she’d given him a small, secretive smile. What was it she’d said?  _ ‘There’s something special here for you.’  _

A deadly disease sure was  _ something special. _

Gen jumped to his feet, deciding his only option was to raise his concerns with the science team. Sticking his head out of the doorway to his small home, he looked around and was pleased to spot Kohaku doing her rounds. 

“Kohaku-chan! I need to see Senku-chan. Or Chrome-chan. Any chance I can sneak out?” 

Kohaku did a quick head count, then nodded. “I think we’re clear! Chrome’s off exploring, but Senku’s in the lab.” She waved for him to follow her, taking a strange winding route towards through the residence area. Ah. A one-way system, of course. It wasn’t as important when most people weren’t out, but definitely a smart thing to have running in case they did need more people working. 

When they arrived at the lab, Kohaku gave two swift knocks. 

“Gen to see you, Senku.” She said. 

“Perfect, let him in!” Senku’s voice was muffled through the door, but even so Gen felt his shoulders release a tension he didn’t realise he’d been holding. It really was a relief to hear the voice of their resident genius again, especially since he and Gen had been inseparable before this disease hit. 

Kohaku held the door open, and Gen slipped inside. 

The lab was as chaotic as Gen had expected it to be. He had no doubt it was an organised chaos, one which Senku could navigate as well as Ryuusui navigated the seas, but it was still chaos nonetheless. 

“Um, Senku…?” Gen waited for the young man to look up, before he gestured vaguely at the space around them. He raised an eyebrow. 

Senku's mask was around his chin. Something in the back of Gen's head flagged that up as unusual and a gnawing worry began to grow in his stomach. The scientist grinned, but it didn’t reach his eyes. “We need to test for the antigen... so I made a test for the antigen.” He gestured to one of the small piles of chaos, on one side of the room. He then turned to the second, larger pile of chaos on the other side of the room. “We also need to be able to test for antibodies. So I made a test for that too.”

Gen nodded slowly, peering curiously over at the first pile, but cautious of getting any closer than necessary. “If you can do all this, does that mean…?”

“A vaccine is on the cards.” Senku smirked, broad and triumphant, but again-- something about it just didn’t reach his eyes. 

“Then… what’s wrong?”

That smile fell into a more bitter thing. “Have a look at the tests.” He nodded at chaos pile number one. 

Gen silently moved over to the table. He tried very hard to understand what all the chemicals were doing, but quickly gave up and instead glanced down to see Senku’s chicken-scratch handwriting over a series of papers. 

_ Ryuusui - pos  _

_ Francois - pos  _

Gen’s heart skipped a beat as he read the next few lines over and over again. 

_ Senku - pos  _

_ Taiju - pos  _

_ Gen - pos  _

_ Yuzuriha - pos _

_ Yo - pos _

_ Minami - pos _

It went on like that. There were only a handful of negative tests. Senku's mask was down because both he and Gen were already infected, and no one else was coming into this space anyway. 

"Senku-chan, this is…" he swallowed, "just your luck... isn't it." Gen’s smile was dark, a hint of panic colouring his tone. 

"I'm not sure how much help a vaccine is going to be right now. It'd take _at least_ a year to make, too. Probably longer." Senku said grimly. Everything about his demeanor was practically a mirror of Gen's. He wasn’t even trying to hide it from the mentalist; his head was tilted just slightly downward (shame?), his smile was wide and sharp (panic?) and his arms were folded firmly against his chest (the number of things he could read from that one...). "We need to focus on getting everyone through this first wave, and then worry about vaccinating to give added protection against reinfecti--" 

Senku coughed, hard. 

His eyes went wide as it developed into a full-blown fit, hunching over as he hacked and spluttered. 

Instinctively, Gen ran towards him, but Senku violently threw a hand up in a ‘stop’ gesture, eyes snapping up to meet Gen’s in warning. The mentalist froze in his tracks, helplessness washing over him like the light from that day 3700 years ago. 

Senku heaved a few deep breaths, seeming to finally regain use of his lungs. 

“You might already have it,” he wheezed, “but it can get worse.” With one final huff, Senku slowly straightened up. “Getting a shit-tonne of these antigens in one go is obviously worse than just having a handful slowly multiplying." He seemed to remember his mask then, swearing under his breath and pulling it back up. "Shit, sorry, I have to move it when the cough hits, I forgot..." 

Gen nodded, but he felt tears prickling at the corners of his eyes. 

Senku must have caught sight of it, because he sighed. He rolled his head back, a hand going to rest on his hip while the other pushed through his hair. “I get it, alright? This sucks. You just have to deal with it though. _We all_ just have to deal with it.”

Gen puffed a sad little laugh, “You’re terrible at the whole providing-comfort thing.”

“Really? Cause I’d say the most comforting thing we can have right now is modern medical technology,” Senku flashed a smirk, just barely visible through the way his cheeks creased under the mask, and clear in his eyes. This must have been the first one he’d offered with any kind of confidence, “and I’m damn well gonna provide that.”

“I’m guessing there’s going to be a looooot of labour involved?” Gen tried to smile, offer his usual joviality in response to Senku's usual confidence. He wasn't sure how convincing it was. 

“Abso-fuckin’-lutely. Roadmap will be done by tonight.” 

A roadmap. He had to admit, that really was comforting. 

“What modern-day definitely-should-not-exist-in-a-stone-world contraption will we be making this time, then?”

“The main issue seems to be breathing. So, obviously, ventilators.” 

“We’re… going to make ventilators. Multiple.” Gen felt his eyebrows shoot into his hairline, as they always did with Senku’s batshit-insane-yet-somehow-achievable plans. With every word the scientist spoke, he found himself remembering all the hopeless battles they'd fought and won already. 

“Yep. It might be tough with a reduced workforce, but we’ll likely see multiple cases reach Ryuusui’s condition at the same time when the people who’ve tested positive get worse. Ryuusui is just about holding on without assisted breathing, but it’s been touch and go.”

“Right… okay.” Gen said. With a deep breath, he stuffed all his concerns into a box in the corner of his mind. There was no time for that right now. Senku had a plan. “Put me to work.”

Senku cocked his head to the side a little, then smiled. The relief was evident. Gen made a mental note not to let his worries show so clearly in future. “I will, when I can. Need to finish the roadmap first, though. Why’d you come out here, anyway?” Senku asked, turning back to the blueprints he’d been drawing up when Gen came in. Gen hadn’t noticed them first, but looking now he could see they were clearly the plans for the ventilator.

“Oh!” Gen remembered, “The boar!”

“The… boar?” Senku glanced back at him, an eyebrow raised.

“Yes. I had boar with my food today.”

“That doesn’t make any sense, we stopped hunting them. Unless…” Senku’s hands went still on the paper in front of him, his jaw going slack. 

“Unless, the only person in this kingdom with enough avarice to throw logic to the wind, decided he desired boar and so would have boar.”

“If Ryuusui ate something the rest of us didn’t eat, it could easily be the source we’re looking for.”

Gen smiled brightly, “Would you like me to ask Chrome-chan to go boar hunting?”

“Find out where that meat was from first. There’s got to be a few dozen sounder of boar around, we don’t have the time to check them all.” 

“Yessir!” Gen offered a mock salute. 

“Good work, mentalist!” Senku grinned, waving him off. 

One small step. Slowly, but surely. 

**Notes for the Chapter:**

> Hope you're enjoying this! It's probably going to be either 2 or 3 more chapters :) my tumblr, if you'd like to make requests or keep up to date or anything: https://www.tumblr.com/blog/view/justdumbfics


	3. Stage 3: Intensive Care

By the end of the week, most of the old-timers were down. 

Some of them, however, were also back up. 

Taiju roared as he ploughed through fields, gathering food and supplies a-plenty. That illness had been one of the roughest things he’d ever experienced! It’d take a lot more than just that to bring him down, though! Magma was never far behind him, and between them they easily managed the work of ten men. 

Senku had taken sample upon sample of Taiju's blood; apparently, comparison of a recovered old-timer with the Ishigami village residents was very helpful in the long term. Taiju had asked what they were doing in the short term, but he knew Senku well enough to recognise the scrunch that had appeared in his brow. He dropped the topic pretty quickly.

Senku had a plan, but it was probably not the kind the scientist was comfortable with. He liked ten-billion percent certainty. Most of his plans involved pushing forward with determination and the belief that as long as they kept going, step by step, they’d make it eventually. Guaranteed. The scrunch in Senku’s brow said ‘there are no guarantees this time’. 

So Taiju decided wasting Senku’s time was a bad idea. Whatever their short-term plan was, it wasn’t going to be easy. Senku needed to dedicate every ounce of energy he could to pushing through this! Explaining things to him wasn’t really on the cards right now. 

Speaking of cards, having Gen down had really shone a light on all the silent work he’d been doing. Taiju hadn’t thought much of the mentalist’s occasional drop by his tent, the short quiet chats about the progress Senku was making and how well the isolation was working. Gen couldn’t have been ill for more than a week, but already the people of the Kingdom were growing restless. It was like whatever spell Gen had been holding them under, with his simple words and gentle prods, had broken now he wasn’t around to supervise it.

Taiju couldn’t help with the science. He couldn’t help with keeping the people under control. 

Everyone had their role to play in the restoration of humanity. His was this: plough through fields, collect supplies and help their little pocket of humanity survive another day. Even if, ultimately, that survival depended on the work of others. 

Gritting his teeth against the helplessness of it all, he threw himself into his work.

* * *

That fucking boar. 

Ryuusui was in a foul, foul mood. 

His condition had improved considerably. By the middle of the week, he had been able move around unassisted, so he had demanded to know the situation. Still wary of their Captain's state of health, they'd refrained from giving him all the details. However, Francois had informed him of how touch-and-go his situation had been. Of course, no one else seemed to notice the slight downward twist of their chef’s lips, or the tenseness in their shoulders, but Ryuusui did. From that alone, he knew it must’ve been incredibly bad. 

A few days later, when the others were finally convinced he could be classed as ‘recovered’, they’d filled him in on the full situation. 

He’d known instantly, beyond a shadow of a doubt, what the source of all this must’ve been. 

“Gen’s right.” He’d said, through clenched teeth. “I went hunting in the mountains because I desired boar. I didn’t eat all the meat I brought back though. Francois refrigerated the remainder, we wanted to use it to provide the Kingdom with a feast when we started making the full-sized ship. That must’ve been what ended up on Gen’s plate.” 

Despite the numerous, loud protests from everyone around him, Ryuusui had then decided he himself would assist Chrome in finding that sounder of boar again. 

That _fucking_ _boar_. 

“Oh my God,” Chrome groaned, “you need to stop!” 

Ryuusui glanced over at him. The two of them were heading across the path Ryuusui had explored all those days ago, with Ukyo lagging slightly behind them.

“Stop what?” 

“Grumbling! Complaining! I get it, you’re annoyed your precious little feast poisoned you, but--”

“No!” Ryuusui barked. Chrome stopped speaking, but raised his eyebrows at Ryuusui, a defiant question hanging in the air. “No.” He growled. “I’ve brought a disease to you all. What kind of captain  _ poisons _ his entire crew?”

Chrome sighed, unsurprised. “I thought that might be it.” He muttered, “Gen mentioned you’d take it hard when you woke up.”

“Did he now…” Ryuusui grumbled. Stupid mentalist and his stupid mind games. Had he actually set up some kind of, what,  _ therapy session  _ for him? With  _ Chrome _ ? Gen must have realised he and Ryuusui would likely go on this trek together… 

“Yes. He did. And he was right.” Chrome stopped walking, crossing his arms over his chest.

Ryuusui ignored the young sciencer, continuing on down the path in silence.

“Oi!” Chrome called. “Stop walking for a second, you idiot!” 

“I am not an idiot.” 

“You are if you think this is all your fault.” Ukyo piped up quietly, having caught up to the now-stationary Chrome. 

“Gen talked to you, too, did he?” Ryuusui finally stopped walking, turning round and crossing his arms. 

“Didn’t have to.” Ukyo shrugged, “It’s not hard to guess how you might be feeling.”

“We are not here to talk about my  _ feelings _ . We have an important task to complete.” Ryuusui waved behind him emphatically. "Those hellish boars will escape us while you stand here!"   


“Ryuusui, stop and think for a second, okay? You have to pull yourself together, and you have to do it quick.” 

Ryuusui narrowed his eyes at Ukyo, mind running through all the facts he had.

Nope. He must’ve been missing some information because he had no idea what Ukyo was getting at. 

The young archer sighed, coming closer as he explained. “You were the first one down, so you’re the first one up. Chrome’s a villager so he probably won’t get it as bad, but the rest of us? Gen’s already down.”

Oh.

“No… Senku will develop medication.” Ryuusui insisted.

Chrome shook his head, “Senku’s prioritised this, uh, ventilator? It’s supposed to help manage the symptoms.

Ukyo nodded his agreement, “We don’t have enough time for anything else. Of the Generals, it's going to be you and Chrome managing the Kingdom for a while.” Ukyo had caught up to him now. He crossed his arms and looked Ryuusui dead in the eyes, gaze hard and lips pursed. “So stop wallowing. You’re a leader. Start acting like one.”

Ryuusui swore under his breath. 

“This isn’t about the boar at all, is it?” He sighed, “This is an intervention.”

Chrome laughed conspiratorially, “It’d be handy to know the source of the disease but it’s definitely not our priority!”

A hint of mischief crinkled the corners of Ukyo’s eyes, his lips quirking up just slightly. “This definitely would have been easier with Gen around, but we’re trying here.”

Ryuusui shook his head, “Have I really been so insufferable?”

Ukyo moved over to the side of the path, sitting down on a rock. Before he could speak, Chrome piped up from behind him. 

“Yeah! You’ve been so bad! It’s not like you did it on purpose!” He flopped down on the grass beside Ukyo’s rock, seeming to deflate. Exasperation seeped from every line of his body. “You didn’t even compliment Francois’s cooking the other night!” 

Ryuusui felt a pang of guilt. He took a seat on the rock beside Ukyo’s, which Chrome had left free. “...Francois doesn’t need verbal affirmation, it’s clear I appreciate--” 

“Y’know, they lied about getting sick.” Chrome huffed. Ryuusui blinked at him, surprised. “They lied!” Chrome said, as if that statement explained everything.

“Senku said the number of antigens didn’t match up.” Ukyo elaborated quietly. “He thinks… when Francois realised you were ill, they intentionally contracted the disease.”

“Why would…” Ryuusui scrunched his eyebrows together, trying to understand. That disease was dreadful. He knew Francois was dedicated to service, but even so… 

Ukyo shrugged, “I’m guessing they wanted to keep doing their job for you. We wouldn’t have let them if it meant risking getting the disease.”

Ryuusui sighed, rubbing his face. He sure was tired. Stupid virus. 

For a few moments, a heavy silence hung between them. 

"I understand." Ryuusui finally said. He chewed over his words carefully before speaking again. "You don't have to worry about my state of mind." 

Ukyo looked mildly suspicious, narrowing his eyes at him. He didn't say anything though, and Chrome just seemed relieved.

"Good!" The young sciencer sprung back to his feet, "Lets catch some boar and get back to the Kingdom, then!"

Ryuusui gave Ukyo what he hoped was an encouraging smile, before standing to lead them down the path once more.

* * *

This was  _ gross _ .

Gen was curled up in bed. He could hardly breathe, his vision was shaky and he was  _ hot _ . Not the good kind of hot, either. The sticky, stuffy,  _ gross _ kind. 

He’d lost track of the days a while ago. It was laughable, really; Senku had counted seconds whilst stuck in stone for 3700 years and Gen? He couldn’t even keep track of the number of times the sun came up. 

That’s what made them such a good team though, right? Complimentary skills. Practically no overlap. 

They were a  _ fantastic  _ team. 

...he really needed to get through this. 

* * *

Everything was wrong. 

Well, no, actually. That was kind of the worst part: everything was going amazingly well. Swimmingly. A dream. In fact, if things had gone this well on any of their other exploits, Senku would’ve been incredibly suspicious as to  _ how _ . 

This time was different, though. Senku had calculated, using the rate of virus synthesis as well as a handful of other factors, he probably had a week at most before he was knocked out. The blood samples had been incredibly useful for the calculations - Senku couldn’t have hoped for a cleaner set of results. 

Unfortunately, all of those lovely, clean, results were saying ‘ha ha get rekt’. 

He wasn’t sure if a patient’s physicality had any bearing on how badly they suffered the symptoms, so he had to assume the worst case. That meant when the symptoms did hit he’d probably be ten billion percent  _ fucked _ , because his fitness levels were absolute shit.

(That wasn’t strictly true - if Senku had developed this level of fitness in the old world, he’d be thrilled with himself. In this world though, and compared to the people who had already been floored by this virus, Senku’s fitness was a steaming hot pile of garbage.)

Everything was wrong, because despite things going smoothly, the calculations were telling him things he did not want to hear - and doing so very slowly. Too slowly. Usually, he’d be totally fine with that! Science was a marathon, not a sprint. But they needed to finish most of the ventilator work before he went down, or he wouldn’t be coming back up. By his calculations, at least 35% of their population would be out, too. Game over. 

The progress on the ventilators lay behind him. He had enough metal thanks to their new mining operation, and the gorilla team were mostly still working so that was all fine. He’d tried to keep Kaseki away, being as old as he was, but the geezer was having none of it. He’d seen the plans and lost all his clothes (they should really work on stretch fibres for him...) instantly. Although, honestly, Senku didn’t really try very hard to discourage him. The villagers had barely developed a sniffle from whatever this was, so on balance it was better to just use Kaseki in an attempt to save the rest of them. They really didn’t have time. It was so frustrating being back to such a small workforce... it was still faster than when it was just him and Taiju, though. He had to remind himself of that. They might’ve regressed, but it wasn’t quite square one, at least. 

He needed to stop getting sidetracked and  _ think _ . It must’ve been the illness, putting his mind in a fog. Senku tapped his pencil against the plans on his table.  _ Think _ . He hacked a cough into his hand, but it was so common by now he barely gave it a second thought. It was like there were ideas and facts drifting around in his head but he couldn’t quite line them up. 

The facts. That was a good place to start. 

  1. He needed to finish the ventilators 
  2. Chrome was unlikely to fall ill too badly.
  3. The ventilators were too complicated to be completed without him.
  4. He didn’t have time to finish them all.



He paused.

2\. Chrome was unlikely to fall ill too badly. 

Of course. Senku smirked. 

Check and mate, virus. 

* * *

That morning, Gen felt his breathing returning to normal. 

The night before had passed in relative ease, too.

He sat up slowly, thinking it too good to be true, but - no, he was definitely feeling better. 

He still felt weak, and exhausted, and hungry, and thirsty - but not  _ gross _ . 

Gingerly, he rose to his feet. His muscles groaned from disuse, but it was nowhere near the fatigue he'd felt before the fever hit. Slowly moving to the entrance of his home, he glanced outside. It was dark, with a biting chill in the air. Winter really was close, now.  He stepped outside, trying to locate one of the Provisions team to get an assessment of the situation, but he couldn’t seem to see anyone. The night shift was much sparser than the daytime one, so it wasn’t really all that strange, but it was inconvenient.   


Best to just get his information from the horse’s mouth, then. 

Taking the winding, one-way route towards the lab, Gen called gently through the door. “Senku-chan?” 

Silence. 

“Senkuuuu-chaaan?” He tried again, stepping just a touch closer. 

That was when he saw it, nestled in the shadows beside the door. 

A single, untouched plate of food. 

Alarm bells ringing loudly in his ears, Gen threw open the door and stumbled inside. “Senku--” his breath caught in his throat at the sight before him. 

Senku was sat with his back to the wall, unconscious. His skin looked clammy and pale, his fringe stuck to his face. Gen didn’t dare take a step toward him though, because of the precarious pile of what could only be described as  _ science _ that lay between them. 

Records. Record, upon record, upon record. Numbered, ordered and organised with accompanying diagrams and notes. To reach Senku, he’d have to risk knocking these piles over and ruining whatever Senku had set up here. 

Just as he was turning to leave - to run, to get help - he spotted one more thing. A note, with his name scrawled in Senku’s unmistakable chicken-scratch handwriting. Gen reached for it as carefully as he could, pulling it down to read it. 

_ Gen,  _

_ If you’re reading this, you’re finally awake. Good. Most of the Kingdom are down. Of the villagers, Chrome, Kohaku and Magma are the only ones still in good condition. The rest of them caught the disease worse than I expected.  _

Gen inhaled sharply, cursing Senku’s luck under his breath. 

_ It’s still only a fever for them, not really Ryuusui levels of bad. Chrome wasn’t as exposed since his work involved leaving the village. He caught a minor version, my prediction is he will recover around the same time as you. Ryuusui and Francois have been handling things, mostly, but they stay away from the science so I doubt they’ll come in here.  _

Gen read that line over a few more times. Senku had written this… knowing that no one would notice his own collapse. So, Senku had been working on all of this science stuff non-stop? To the point where no one expected to see him leave the lab? Despite his symptoms? Unbelievable. Gen felt a familiar flutter in his chest, one he found himself feeling more often than not. It was the same one he felt when looking at the writing carved into that tree all those months ago, or when looking up at a madman on a roof generating electricity for the first time in thousands of years.  


_ I’m still working on the ventilators, but I’m also leaving full instructions on how to finish them, in case I go down before they’re done. _

Oh. Oh, no.   


_ Chrome will understand what to do. It sucks that Kaseki’s down, but he already did most his work.  _

They had to finish it without Senku?! 

_ Before you panic, you’ve got my help, still. Everything you could need, I’ve left on the records. I didn’t have time to listen to them back, and I was making them while I worked on other stuff, so sorry if they’re not the cleanest recordings. They’re in the right order, so don’t go mixing them up.  _

That was it. That was all he’d written. No ‘I’m glad you’re okay, Gen’, or ‘don’t worry Gen’, of course not, none of that. Gen felt a sharp laugh escape his throat. To the point, as always. Looking up from the note slowly, he took stock of his surroundings with new eyes. He felt hysteria bubble in his chest, sparking another pointy little laugh. 

They were really going to just… they had to, just... do this. 

He took a deep breath. He trusted Senku.   


Time to find Chrome. 

**Notes for the Chapter:**

> Thank you for reading as always, hope you're enjoying this! ^^ pls kudos & comment! honestly its so motivating knowing people are actually reading this and not hating it ahaha also my tumblr is here : https://www.tumblr.com/blog/view/justdumbfics ! See you next time for the conclusion!


	4. Stage 4: Final

**Summary for the Chapter:**

> Welcome to the finale!! I hope you've enjoyed reading this, I've loved writing it!

The air in the lab was still and heavy. Two young men stared each other down. 

In his defence, Chrome was under quite a lot of pressure. An insurmountable level, in fact - the kind you’d need to forge diamonds, you could say. As this thought sprung to Chrome’s mind he almost instantly discarded it, a bitter taste on his tongue. He never thought new scientific knowledge could make him feel so… ill. 

Gen was staring at him, but not with the kind of wide-eyed shock one would expect after Chrome's outburst. No, Gen’s gaze was that of a man quietly recalculating the situation around him.

“Chrome-chan… that wasn’t very nice.” He said simply, softly. 

Gen had walked in and asked one very simple question: why have you only touched three of the records? 

The rest of them were still piled up in the correct order, but now carefully stacked at the side of the lab. Gen had noticed that, despite having been in the lab for hours now, Chrome seemed to have only used three of the records. So he asked a simple, valid question: why?

Chrome had reacted as though Gen had punched him in the face. Then murdered his first born child. And fed the corpse to a dragon. 

The young science-er took a deep breath. In, and out. 

“I don’t… I’m sorry, I didn’t mean to shout.” He could feel his voice cracking and he hated it. He needed to be strong right now. He needed to be _Senku_. He couldn’t though. He didn’t want this, he didn’t want any of it, not like this. 

“What’s wrong…?” Gen folded his arms into the wide sleeves of his winter Hakama, taking a few slow steps towards him. 

“These are…” Chrome swallowed, his eyes tired as they met Gen’s. It was probably a bad idea to tell the mentalist, but he didn’t think he could hide it from the other man. Gen’s eyes narrowed in that moment, and Chrome knew he didn’t stand a chance. A sigh spilled from his mouth, taking the tension in his shoulders with it. He took a heavy seat on a stool by the lab’s workbench, drooping forward in visible defeat. The sorry sight was a far cry from the viciousness of the verbal assault he’d launched only a few moments ago. 

“These are…?” Gen prompted, coming to stop a few paces from the young man. “Come on, what is it?” 

“These.” Chrome gestured to the three records on the table. “I don’t-- just listen to it.” 

Gen raised an eyebrow, but took cautious steps to the record player. He kept an eye on Chrome at all times, like he was afraid of an imminent eruption. 

“Which one?” He asked. 

“Top one.” Chrome’s voice was a mumble now, as he folded his arms on the bench and let his chin fall onto them. 

Gen set it into the record player, and turned the handle. 

_“Yo.”_

Senku’s voice. Gen must’ve known it would be, but Chrome didn’t miss the way the mentalist still flinched. It was a small movement, but it looked huge on someone with a mask as thick as Gen’s. 

_“You must’ve realised with the last record that that’s it. That’s all you need, to finish the stuff. Old man Kaseki an’ me did the rest of the work. The remaining records here are going to be an encyclopedia. I ain’t a psychic, and I don’t got the time to record everything I know. I’m gonna be guessing at what you might need in the futu--”_

The voice stopped abruptly as Gen’s arm went still. He was staring at the record like it had spouted three legs. 

The silence that followed was deafening. 

“Yeah.” Chrome said. It sounded awfully weak, even to his own ears.

Gen turned to look at him, the movement slow and forced. 

“Senku’s a realist.” He said simply, tone so void of emotion that Chrome could practically hear Gen’s brain malfunctioning. “Of course he’d prepare for the worst case scenario. That doesn’t mean he thought it would happen.” 

Chrome couldn’t even pretend to buy that. Senku was a realist, sure, but he was also logical to a fault. Why waste time making all these records if he didn’t think the probability of needing them was high enough? 

Gen seemed to read those thoughts in his eyes. He clicked his tongue. “Thinking about it doesn’t do any of us any good. That’s the least logical thing to do, right? That’s what he would say. He’d say all we can do is put ten-billion percent of our effort into finishing this ventilator and helping him pull through!”

Chrome swallowed, straightening up in his seat. “You’re right… you’re right. I think he had a brainwave too, because it’s not just ventilator plans here.” He waved to a few things spread out on the workbench before him.

“What?” Gen nearly tripped over himself as he rushed back to see what Chrome was talking about.

“Yeah, I think he figured out how we could make, uh, analgesics? And there are some other medicine plans, too.”

“Analgesics are-- painkillers?" Gen sputtered, "I don't recognise the others... specific help for this kind of virus, maybe?” He looked over the blueprints on the table, willing them to make sense. It was hopeless though, science never was his thing.

“Yeah, he said something like that, on the second record. Apparently, these can help manage the symptoms?” 

“Yeah… that makes sense. And given we made antibiotics already, I’d guess it definitely wasn’t too far out of our scope…” 

Chrome nodded to a few dishes of chemicals and other substances he’d still yet to fully label. “He already started work on it, he must’ve been craaazy busy in here.” 

Gen made a sound which was probably meant to be a laugh, but it came out more like… a cross between a scoff and a sob. 

“Yeah, we knew that though. He made all those records, and practically finished the ventilator, and he was sick the whole time.” 

Chrome gritted his teeth, frustrated tears pricking at his eyes. Breathe. In, and out. 

“We can do this.” He said, more for himself than Gen. 

“...yeah. Yeah.” Gen said, eventually. “Yeah, Senku believed we could. Since when has Senku ever been wrong?” 

If you say something with enough conviction, you can trick yourself into believing it’s true. 

“We can do this.” 

* * *

Perhaps the greatest testament to a leader’s skill is how well the people cope without them. Can you build something strong enough to withstand you absence? In a remarkable show of solidarity and faith, the Kingdom of Science had come together. 

It was a small blessing that Senku had fallen ill while so many of the kingdom were themselves too ill to notice. It meant that rather than a mass wave of panic when their leader went down, it was a quiet whisper that spread through them instead. People woke, slowly took stock of the situation, and had the space to come to terms with it. They could figure out what they should be doing, how to help Chrome and how to help the Kingdom.

Also, anyone who seemed like they might panic could be easily controlle-- sorry, _comforted_ by their resident mentalist. 

The point being, Senku falling ill had unified the people in a way the Generals couldn’t have dared to dream about. Everyone wanted Senku back, and that was a powerful, unifying goal. 

It barely took any time at all, once enough of the citizens’ symptoms began clearing up, for them to throw themselves back into their work. Those responsible for food and other upkeep work were back at it as soon as they were able, restocking their (dangerously low) supplies and keeping everyone fed and watered. Everyone whose main task had been related to the ship building was now on standby for Chrome’s use; at any given time, he needed labour or explorers or both. It also paid to have at least one modern-timer on hand at all times, since there were some things Senku had been forced to write down. 

There were, as Senku had predicted, still many who were struggling to recover. However, everything was going as well as it possibly could be. Except, of course, for the one thing they all needed most. 

Senku had taken this worse than anyone else in the kingdom. He was barely breathing, and his fever was sky-high. 

Yuzuriha sat by his bed, chewing her bottom lip as she watched the shallow rise and fall of his chest. Her hands curled into her dress, worrying at the fabric incessantly. She stared at the rag on his forehead, wondering if she should change it again. It really hadn’t been long enough, but she was itching for something to do. 

She glanced out the window for what must have been the tenth time in as many minutes. The sun had barely moved. 

The door swung open and Yuzuriha nearly jumped out of her skin.

“Yuzuriha!” Taiju boomed, coming over with two bowls of food. “Here, you should eat!”

“Oh, thank you Taiju.” She smiled, accepting the bowl as Taiju took a seat beside her.

“How is he?” Taiju asked, with a forced air of nonchalance that he really could not pull off. Yuzuriha would’ve rolled her eyes if she didn’t think the act was a little bit endearing. 

“Honestly? I don’t know… I haven’t noticed a change, at least.” 

“That’s good! It hasn’t gotten worse!” Taiju smiled brightly.

“It also hasn’t gotten better.” Yuzuriha’s smile was strained. She regretted the words she’d spoken as soon as they left her mouth. She could see, in the twitch of Taiju’s mouth and the sudden dim of his eyes, that he hadn’t really thought of it like that. 

They sat in silence, picking at their food. 

In the stillness of the room, sat beside their best friend’s bed, Yuzuriha felt like she could hear the beep of a heart monitor. 

* * *

Ryuusui was so very relieved when Chrome told him about the painkillers and other medication. Even more so when Chrome had told him they were _finished_ . Having lived through the dastardly virus himself, he knew first-hand how much he would’ve paid for even a single paracetamol pill! Never mind stronger painkillers _and_ medication for this virus specifically! He had wondered at the time why Senku hadn’t made at least some basic painkillers for him, but he’d since been given missing pieces of the puzzle. The crazy scientist had to prioritise goals, make blueprints for them and leave detailed instructions for Chrome who, intelligent though he was, _couldn’t read_. To top it off, he’d done it all in a fever-induced haze. Rushing through painkiller production when only one citizen needed it would not have been logical, even if he’d been in a state to consider trying it. 

Now, though? 

Now, they had several villagers with high labour potential out-of-commission. Villagers who would probably be able to work again given some pain relief and other symptom management. Some of them might even recover off the back of this medication alone, if Senku's hypothesis was correct.

Ryuusui was staring at his desk, Francois by his side, as he finalised his distribution plan. He had finally managed to figure out priority for the medication; they were reliably producing them, yes, but not _quickly_ producing them. There was also a possibility of them running out. The order in which they got people back on their feet was going to be crucial. Help too many of the vulnerable first, and we don’t have the manpower to keep producing the chemicals. Help too many of the high-labour potential ones first, and the vulnerable die before you get to them.

He was finally happy, though. He’d run this past the other generals, and compare it with their own ideas. Then, they’d be able to--

A body crashed into the room, barely standing. 

Chrome?

The young man had just stumbled in, with a crash that made even Francois jump. His eyes were manic, with heavy bags dragging them down. Had he slept? Eaten? 

“It’s done!” Chrome announced. “The ventilator… the prototype is done, and we’ll have more by the end of the week.” 

Ryuusui’s eyes widened. 

“We can help Senku!” Chrome almost sobbed, his haggard form slumping even closer to the ground. “Finally… finally!” 

It took Ryuusui a moment to register the words that were being said. His mouth curved into a wide, wicked grin.

“Then what are we waiting for?!” He boomed, triumphant laughter breaking free of his throat and filling the air. He strode across to where Chrome lay, grabbing his arm to heave him to his feet. “Let’s get him hooked up so you can get some sleep.” 

Chrome laughed, bright and cheerful and everything they’d lacked since the moment Senku went down. 

* * *

It was hot, and stuffy, and hard to breathe. 

159823, 159824, 159825… 

It had been at least 3 days since he’d stopped working. He didn’t think he’d need to count, since he figured he’d wake up soon enough and the others will have been tracking the days. After at least a day of this strange, in-and-out of consciousness, though, he’d decided maybe counting was for the best, if only to manage his own sanity. He had to estimate a start point, but he’d been counting ever since. Well, whenever he was awake, he had been. He wasn’t an idiot, he knew rest was important in a situation like this but when he wasn’t resting? When his body would rather scream at him about something or other than just _go to sleep_? He needed something to do in those hours of restlessness. 

He knew people were by his bed. Probably Taiju and Yuzuriha, from the snippets of conversation he picked up. He heard Gen come by fairly often, too. He couldn’t speak to them, though. He knew he’d sound like shit, and that would just stress them out even more. No, better for them to think he was peacefully resting and recovering. He could just spend his waking hours counting, instead. 

Besides, it was entirely possible the rest of humanity would be down by the time he got up anyway. It was a grim kind of logic, and it was far more likely that at least one person would be fit to time-keep on any given day, but Senku was a man who prepared for the worst case scenario whenever possible. An accurate measure of time was one of the most important tools he could have, for so many reasons, and not something he should risk losing. So it was sensible to count whenever he could, give himself some sense of how much time was passing. 

It was one such restless bout of wakefulness when he felt something come over his mouth. People had come into the room 1137 seconds - so 18.95 minutes - ago. He’d assumed it was just guests again, but found it odd that they were completely silent.

It made sense now. It seemed they were setting up a ventilator! 

He _knew_ Chrome would do it. 

Now _this_ was exhilarating. 

He blinked his eyes open, turning his head to take stock of the situation. Unsurprisingly, it was Chrome hooking him up. The ventilator was... mechanical? He had told Chrome, on the record, that they could scrap the mechanical design for a hand-powered one, if things were looking hairy. Of course, there were far more risks with something like that as it would require a continual, sustained input of energy from the user. Possible, yes, but would he risk the lives of the kingdom on someone’s ability to pump steadily? Or, would he put the pressure of _keeping someone alive_ on one of the kingdom’s people? It didn’t sit right with him. Too many ways for too many things to go wrong. 

Clearly, Chrome had agreed. He’d finished the mechanical one, and in only around three days. What a fuckin’ badass. 

Chrome seemed to notice him then, his tired eyes lighting up with a broad smile. 

“Senku!” He was saying, bright and happy, and then the ventilator kicked in. 

It was instantly clear to him that it was doing its job. The strain was off. He still felt like crap but this was definitely the biggest hurdle overcome. His body had the support it needed now! 

“Chrome…” He gasped, moving the mask just slightly so he could speak for a moment. “You crazy asshole, you actually pulled it off…” 

He couldn’t put as much energy into it as he wanted to, but he hoped the tears in his eyes and the grin on his face would convey that for him. 

It seemed to work, because Chrome teared up too, his grin splitting his face as he offered up a high five. Senku raised a hand to meet his apprentice, and the room erupted in cheers. For the first time, Senku took stock of the others who were there. All the generals, Taiju, Yuzuriha - everyone, on their feet and healthy. Holy shit. 

The tears fell freely down his cheeks as he laughed under his mask.

_They were going to be okay._

* * *

Senku only stayed on the prototype ventilator until he realised he had been the recipient of the first one, and that the others weren’t completed yet. 

“Are you stupid?” He’d groused, “I’m young. Ryuusui pulled through without any assistance, so did Gen. If we want as many people to survive as possible, these go to the weaker members of the kingdom first. That’s the only logical thing to do, since we’re obviously going for the option where _everyone_ lives.” 

He wouldn’t take no for an answer, so Chrome and Gen had to cart the thing to one of the less fit members of their kingdom (“He’s barely breathing and he’s still making us do all this _labour_.” Gen had whined). Luckily, Tsukasa had only revived fighters in their prime. That meant there was only one modern-timer and a handful of older folk from Ishigami village ahead of Senku in the queue. 

By the end of the week, they had enough units to go round. Senku had thankfully survived that long, and had been given one again. 

Not long after that, a handful of Senku’s closer friends gathered in his room. He was sitting up, looking so much healthier. Gen felt tears pricking at his eyes, unable to stop himself comparing this Senku to the one he’d found slumped in the lab. Everyone else seemed to be having similar thoughts because the air was heavier than the damn ship they were building. 

“I wish Senku-chan would just _listen_ sometimes.” Gen complained, trying to distract from the sheer emotion in the room. “Whether he likes it or not, he’s the most important person around right now. He should’ve accepted the first ventilator.” 

“Don’t talk about me like I’m not here.” Senku rolled his eyes, looking pointedly at Gen.

Chrome shrugged, ignoring Senku to look at the mentalist. “He doesn’t see himself that way. I’m not sure that’s a bad thing.” 

“Oi, Chrome, not you too!” Senku’s head whipped to the young science-er. Chrome was grinning, a glimmer of mischief in his eyes. Yuzuriha giggled from her spot in the corner beside Ukyo, who was barely biting back a smile of his own.

Gen sighed, “Maybe not. A leader should recognise his own value in a pack though. For all he spouts about logic, he ignores it himself sometimes.”

“ _Ignoring me_ is definitely the least logical thing happening right now!”

The snickers and giggles around the room grew into loud laughter, the atmosphere becoming one of relief. 

“I’m glad you’re okay, Senku.” Gen said quietly, finally addressing the scientist. “We all are.” 

Every pair of eyes in the room landed on Senku, each with a unique cocktail of heavy, unspoken emotion. 

Senku ran a hand through his hair, sighing. “Good. Hold onto what you’re feeling right now, cause it’ll power you through phase 2.”

“Phase 2…?” Ryuusui raised an eyebrow. 

“Reinfection ain’t off the cards. We’re unlikely to catch it again so soon after recovering, but it’s a real threat in the future. Phase 2 is vaccination.” 

He flashed them a sharp smile. 

“I hope you’re ready to see the roadmap.”

**Notes for the Chapter:**

> And so it concludes!!  
> I do hope you've had a fun read! I'm always taking prompts if you want anything dr stone written ;) Until next time! I have (at least) one more idea for a fic in this series so stay tuned I guess ahaha

**Author's Note:**

> Hope you enjoyed! Please kudos and comment, or I feel like I'm writing into the void :') also here is my tumblr, which I only just made now that i want to write more fics haha if you like my writing, I'm probs gonna end up opening requests for fics when I run out of ideas, which will be done through tumblr :') https://www.tumblr.com/blog/view/justdumbfics


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